What is Green?

Determining a building product's true environmental impact is not always easy

Readers of The Journal of Light Construction are no
strangers to the green building movement. There are now several
dozen residential green building programs around the country
with thousands of homes built in the past few years to their
standards. Many of you participate in those programs, or have
launched your own green marketing efforts.

Energy Star Homes, which focuses on energy efficiency, has
seen a dramatic surge in participation, with over 100,000 homes
built through the program. Even the National Association of
Home Builders — far from a fringe environmental advocacy
group — has taken an active interest in green building,
with the formation of a green building subcommittee and the
passage of a green building policy last May.

A key aspect of green home building is the selection of green
building products — materials that carry a minimal
environmental impact. But just what makes a given product
"green"? How do you evaluate the relative greenness of
different products? How do you find green products? How do you
distinguish the truly green from the greenwash?

We at BuildingGreen, Inc., and Environmental Building
News have been researching and writing about green building
products for more than ten years. We've come up with specific
criteria for evaluating building products and identifying those
we consider green — a process we use in screening
products for our GreenSpec directory. Here's what we've
come up with.

Defining Green

Evaluating building products for their "greenness" involves
something called "life-cycle assessment" (LCA). This is an
emerging science that considers a product's environmental
burdens throughout its life cycle — from resource
extraction, through manufacturing and use, and ultimately to
disposal or recycling into a new product. Because most building
materials are in use for a long time, the use phase of a
material's LCA is particularly important.

To complicate matters in LCA work, we consider lots of
different types of impacts. We consider impacts on the resource
base — harvesting timber, for example, or extracting
mineral ores. We consider air pollution and water pollution
emissions during manufacture and shipping, one measure of which
is the "embodied energy" of a material. We consider what effect
a product may have on the operation of a building — for
example, the product's impact on the energy use of the building
or the maintenance requirements (and those environmental
impacts). And we consider what the impacts of a material might
be on the people working or living with it — indoor air
quality concerns.

The problem is that with so many different types of impacts,
when we compare one product with another, we are often
comparing apples to oranges. The challenge in evaluating green
building materials is in balancing all the
considerations.

Distant dream. The Holy
Grail of the green building movement would be a database in
which the life-cycle environmental impacts of different
materials were fully quantified and weighted so that a builder
or designer could easily see which material was better from an
environmental standpoint. Though efforts are afoot along those
lines — for example, the BEES software that has been
developed by the National Institute of Standards and Technology
(NIST) — we are not even close to fully realizing that
goal. We are a long way from having a truly objective way to
compare the greenness of building materials, but we can still
make informed decisions about selection.

Let's take a more detailed look at some of the criteria that
can be used to define building products as green. Through this
process, you should get a sense of the tremendous variety of
green building products and the many characteristics that can
be used in identifying them.

Products Made With Salvaged, Recycled, or
Agricultural Waste Content

The raw materials used to produce a building product —
and the source of those materials — are key determinants
of green.

Salvaged products. Whenever
we can reuse a product instead of producing a new one from raw
materials — even if those raw materials are from recycled
sources — we save on resource use and energy. Many
salvaged materials used in buildings (bricks, millwork, framing
lumber, plumbing fixtures, and period hardware) are sold on a
local or regional basis by salvage yards, but some are marketed
nationally.

Products with recycled
content. Recycled content is an important feature of
many green products. From an environmental standpoint,
post-consumer is preferable to post-industrial recycled
content. "Post-consumer" means that some portion of the raw
materials used in manufacturing the product was diverted from
the waste stream. Plastic lumber made from recycled HDPE
grocery bags and cellulose insulation made from ground-up
newspapers are good examples. "Post-industrial" refers to raw
materials that were waste products from industry but had never
actually been in use. Iron-ore slag used in mineral wool
insulation, fly ash used in concrete, and PVC scrap used to
make shingles are examples of post- industrial recycled
materials.

Products made from agricultural
waste material. Some green building products are made
from agricultural waste products. Approximately 140 million
tons of straw are produced annually in North America from the
harvesting of wheat, barley, rice, and other grains. In the
past, most of that straw was burned in the fields, but
pollution-control regulations increasingly ban that practice;
using the material to produce building products is a great
alternative. When it's chopped up, mixed with a binder, and
compressed into panels, straw produces a superb particleboard
product.

Products That Conserve Natural
Resources

Aside from salvaged or recycled content, there are a number of
other ways that products can contribute to the conservation of
natural resources. These include products that serve a
particular function while using less material than the standard
solution, products that are especially durable or
low-maintenance, wood products that carry Forest Stewardship
Council certification, and products made from rapidly renewable
resources.

Products that reduce material use. Products meeting
this criterion may not be distinctly green on their own but are
green because of resource efficiency benefits that they make
possible. For example, drywall clips allow the elimination of
corner studs, engineered stair stringers reduce lumber waste,
pier foundation systems minimize concrete use, and concrete
pigments can turn concrete slabs into attractive finished
floors, eliminating the need for conventional finish
flooring.

Products with exceptional durability or low maintenance
requirements. These products are environmentally
attractive because they need to be replaced less frequently, or
they require less maintenance. Fiber-cement siding and
fiberglass windows, for example, can be considered green
because they last longer and require less maintenance than
standard products.

Certified wood products.
Third-party forest certification, based on standards developed
by the Forest Stewardship Council (FSC), is the best way to
ensure that wood products come from well-managed forests. Wood
products must go through a chain-of-custody certification
process to carry an FSC stamp. While there are now other forest
certification systems, including the Sustainable Forestry
Initiative (SFI) — which has been strengthened
significantly in the past several years — the FSC
standards are still the most rigorous and the most frequently
specified in the green building movement.

Rapidly renewable products.
Some products are considered green because the raw materials
used in producing them are replenished quickly. Natural
linoleum flooring is made from linseed oil (an agricultural
crop). Cork, which comes from the bark of certain oak trees, is
harvested sustainably on an eight- to ten-year cycle. A new
class of concrete form-release oils made from plant oils is
both nontoxic and fully biodegradable. Jute, sisal, and coir
are examples of natural fibers that are used in everything from
wall coverings to erosion-control geotextiles. Because sunlight
is generally the primary energy that produces those raw
materials (via photosynthesis), they are often less energy
intensive to produce than the conventional products they
replace.

Green Products vs. Green
Building

It's important to consider the distinction
between green building products and green building.
One could build a green home with few materials
specifically defined as green. A really compact,
highly energy-efficient house on an in-fill site
close to public transit, for example, would likely
be defined as green even if all of the materials in
the house were conventional — no
recycled-content decking or linoleum flooring or
certified wood.

Conversely, green products can be used in dumb
ways that result in buildings that are far from
environmentally responsible. One could use nothing
but recycled-content products but fail to pay
attention to energy efficiency or where the house
is built. Or one could ignore moisture control and
end up with a mold farm that makes the homeowners
sick. That certainly isn't green.

Green building involves more than just the
selection of green products. It involves such
issues as siting the home wisely, minimizing
dependence on automobiles, protecting the ecosystem
around the home, designing the home to benefit from
passive solar energy, providing an energy-efficient
building shell, and incorporating building science
principles to ensure that the house will be safe
and last a long time.

That said, however, substituting green products
for conventional products can make the difference
between a good home and a great one from an
environmental standpoint.

Products That Are Green Because of What
Isn't There

Some building products are considered green because they are
alternatives to conventional products that are considered
hazardous.

Alternatives to conventional
preservative-treated wood. CCA-treated wood, which
contains both arsenic and chromium, poses a health hazard and a
significant environmental risk during disposal;
pentachlorophenol (penta) and creosote are considered
carcinogens. Alternatives to those chemicals, such as ACQ,
copper azole (Wolmanized Natural Select), and borates can thus
be considered green.

Alternatives to ozone-depleting
substances. Ozone-depleting substances are being
eliminated through international agreement. As of this year,
for example, polyisocyanurate insulation is no longer made with
ozone-depleting HCFC-141b as the blowing agent. But in a few
categories, the majority of products still contain or use
HCFCs, including certain categories of foam insulation
(extruded polystyrene and high-density spray polyurethane) and
compression-cycle hvac equipment. A product can be considered
green if it serves as an alternative to one of those widely
used products.

Alternatives to PVC.
Polyvinyl chloride (PVC), or vinyl, products contain up to 40%
chlorine by weight, and if an accidental fire or improper
incineration occurs, hazardous chlorinated hydrocarbons, such
as dioxins, can be generated. The plasticizers used to make
many PVC products soft are also considered hazardous. The
debate about the relative risks of PVC has been quite heated
over the past five years, with Greenpeace and other
environmental groups decrying PVC as dangerous, while the
plastics industry touts such products as green because of their
durability and low maintenance requirements. In the green
building field, the use of PVC is generally discouraged, so
some products may be considered green because they are non-PVC
in an application served primarily by PVC products.

Alternatives to mercury and other
components considered hazardous. Fluorescent lamps with
low mercury levels can be considered green, as can certain
non-mercury lighting technologies, such as LEDs (light-emitting
diodes). The absorber surfaces of solar collectors can
similarly be considered green if they are made without
chromium.

Natural or minimally processed
products. Products that are natural or minimally
processed can be green because of low energy use and low risk
of chemical releases during manufacture. These can include wood
products, agricultural or nonagricultural plant products, and
mineral products such as natural stone and slate
shingles.

Products that reduce or eliminate
pesticide treatments. Periodic pesticide treatment
around buildings can be a significant health and environmental
hazard. The use of certain products can obviate the need for
pesticide treatments, and such products are therefore
considered green. Examples include physical termite barriers,
borate-treated building products, and bait systems that
eliminate the need for broad-based pesticide application.

Products that reduce pollution or
waste from operations. Alternative wastewater disposal
systems reduce groundwater pollution by decomposing organic
wastes more effectively. Porous paving products and green
(vegetated) roofing systems result in less stormwater runoff
and thereby reduce surface water pollution and sewage treatment
plant loads. Masonry fireplaces and pellet stoves burn fuel
more completely with fewer emissions than conventional
fireplaces and wood stoves. Recycling bins and compost systems
enable occupants to reduce their solid waste generation. All
these products are green because they improve the environmental
performance of building operations.

Products That Reduce Environmental Impacts
During Construction, Demolition, or Renovation

Some building products achieve their environmental benefits by
avoiding pollution or other negative environmental impacts
during construction, renovation, or demolition. While this is a
fairly small category of products, it is nonetheless important.
Erosion-control products, foundation products that eliminate
the need for excavation, and exterior stains that result in
lower VOC emissions into the atmosphere all reduce the impact
of new construction. Low-mercury fluorescent lamps reduce
environmental impacts during demolition and renovation. Access
flooring systems and modular carpet tiles minimize
environmental impacts during renovation, because they make
reconfiguration of spaces much faster and reduce waste.

Products That Save Energy or
Water

The ongoing use of energy in a building is often its most
significant environmental impact — and one that usually
far outweighs the impacts associated with building that
structure. Water consumption is becoming a more and more
important consideration in buildings as droughts become more
common and more severe.

Building components that reduce
heating and cooling loads. Examples include structural
insulated panels (SIPs), insulating concrete forms (ICFs), and
high-performance windows and glazings. As these energy-saving
products gain market acceptance, the performance level needed
for a product to be considered green can rise. For example,
while insulated-glass windows with a low-e coating may have
been enough to designate a window as green several years ago,
today it may take multiple low-e coatings or other green
features, such as more durable or recycled-content frame
material.

Equipment that conserves
energy. With energy-consuming equipment such as water
heaters and refrigerators, it is fairly easy to identify green
products — by setting a threshold for energy performance.
Some green building programs identify products labeled by
Energy Star as the standard for green. Other programs or
directories may define tougher standards or include other
criteria, such as durability, in addition to energy
performance.

Renewable energy and fuel cell
equipment. Equipment and products that enable us to use
renewable energy instead of fossil fuels and conventional
electricity are highly beneficial from an environmental
standpoint and are generally considered green. Examples include
solar water heaters, photovoltaic systems, and wind turbines.
Fuel cells can also be considered green, even though fuel cells
today nearly always use natural gas or another fossil fuel as
the hydrogen source; they are considered green because
emissions are lower than those of combustion-based equipment
and because the use of fuel cells will help us move beyond
fossil fuel dependence.

Fixtures and equipment that conserve
water. Products that conserve water are often considered
green, but there may be other considerations. All toilets and
most showerheads, for example, now meet federal water
efficiency standards, but not all of those products perform
satisfactorily. A green designation may require independent
evidence of superior performance.

Products That Contribute to a Safe Indoor
Environment

Buildings should be safe to live and work in, and product
selection is a significant determinant of indoor environment
quality. Green building products that help to ensure a
healthful indoor environment can be separated into several
categories:

Products that release insignificant
levels of pollutants. Included here are zero- and
low-VOC paints, caulks, and adhesives, as well as products with
very low emissions, such as nonformaldehyde-manufactured wood
products. Just how low the VOC level needs to be for a given
product to be considered green may vary by program and
directory.

Products that block the
introduction, development, or spread of indoor
contaminants. Certain materials and products can be
considered green because they prevent the generation or
introduction of pollutants — especially biological
contaminants — into occupied space. Duct mastic, for
example, can block the entry of mold-laden air or insulation
fibers into a duct system. Rainscreen products can help
buildings dry out after wetting occurs. Entryway "track-off"
systems remove pollutants from the shoes of people entering.
Coated ductboard — compared with standard rigid
fiberglass ductboard — prevents fiber shedding and helps
control mold growth. And linoleum helps to control microbial
growth because of the continuing process of linoleic acid
oxidation.

Products that remove indoor
pollutants. Removing stale indoor air is an important
air quality practice, so a wide range of ventilation products,
filters, and radon mitigation equipment can be considered
green. In some product categories, other considerations may be
important. Noise may be a consideration for bathroom fans, for
example, because they are more likely to be used by homeowners
if they're quiet.

Products that warn occupants of
health hazards in the building. Carbon monoxide (CO)
detectors and test kits for lead paint, VOCs, mold, and other
potential hazards can help keep homes and workspaces safe, and
so can be considered green. In some cases, performance criteria
are also considered — some CO detectors are not
effective, so evidence of good performance may be necessary for
a green designation.

Products that improve light
quality. There is a growing body of evidence that
natural daylight is beneficial to our health and productivity.
Products that enable us to bring daylight into a building, such
as tubular skylights, can be considered green for that reason
(in addition to their energy-saving benefits).

Finding Green Building
Products

Selection of green building products as part of an overall
green design strategy makes a great deal of sense. But finding
such products can be difficult. Green building products may not
be available in all building supply centers. Some are more
expensive or are considered fringe products. To get your local
supplier to carry green products may take some convincing. If
you are committed to using FSC-certified lumber, for example,
besides letting your supplier know that, you could help out by
doing the research on product wholesalers your supplier could
purchase from. Just a few customers asking for green products
can make a huge difference — try it.

You may also find it challenging to identify which products are
actually green — compared with those being marketed as
green. "Greenwashing" is fairly common today, and few places
exist where you can find independent verification of green
claims. Specific labeling programs such as Energy Star,
GreenGuard, and Green Seal can help, and there are a handful of
green products directories, including our own:
GreenSpec. Such directories can be a valuable
resource.

Alex Wilsonis president of Brattleboro, Vt.-based
BuildingGreen, Inc., which publishesEnvironmental Building NewsandGreenSpec,
the leading national directory of green building
products.GreenSpeccarries no advertising and includes more
than 1,650 products. It is available in a print edition or as
part of BuildingGreen's premium web content. The fourth edition
will be available in November. For more information, visit
www.buildinggreen.com or call
800/861-0954.